SANTA CRUZ -- The third volume of Santa Cruz's Historic Building Survey is out, and the city is loosening rules to encourage property owners to remain on the list and make improvements easier.

The first full survey conducted since the Loma Prieta earthquake has identified 95 buildings and 30 walls or other features to be listed among the city's historically significant sites unless owners opt out by Feb. 1. The $75,000 survey took 10 years to complete.

The city sent letters last month to property owners whose sites had been determined to have historic value. While previous surveys published in 1974 and 1989 were dominated by residential buildings from the 19th and early 20th centuries, this survey features mid-20th century architecture and a number of commercial properties.

Included among those are the Water Street Medical Plaza, a collection of 1964 buildings designed by Frank Lloyd Wright associate Aaron Green; a landmark 1948 Neo-Craftsman stone cottage on West Cliff Drive at Stockton Avenue; and the 1953 former Tastee Freeze that is now Charlie Hong Kong on Soquel Avenue. A number of older buildings on the Soquel Avenue corridor also were added, including Shopper's Corner, a Streamline Moderne building, and the old Santa Cruz Hospital, an Italian Renaissance building known now as Branciforte Plaza. Both were built in 1929.

Expanding the historic registry helps "to retain the character of the city," Planning Director Juliana Rebagliati said. "It ties us to our history," she said.

The city's general plan calls for providing incentives for rehabilitating historic properties and streamlining alteration permits. With the third survey, the Planning Department simultaneously has recommended several rule changes to be finalized Tuesday by the City Council and will host workshops Wednesday and Jan. 9 to answer questions from property owners.

Changes in city ordinance include an assurance that the historic designation affects structural alterations, not interior changes or exterior paint color or landscaping. Also there are provisions for larger accessory dwellings, multifamily uses in single-family residential zones and reductions in parking requirements.

Podiatrist Tim Blakeslee wants to convert the attic of his 1882 Queen Anne cottage into two bedrooms and a bathroom to accommodate a growing family. But because the historic home has two floors that aren't connected it doesn't conform to zoning and multifamily use isn't allowed.

"This ordinance enables us, with the approval of the planning folks, to enhance the function of the home," he said.